NSF-SNSF: HormEsis RespoNces in pHytoplankton NAnotoxicology and ImpliCations for Environmental Risk Assessment

Nanotechnology can provide important advances in many areas, including renewable energy, advanced water treatment, medicine, food protection, and others, to increase sustainability. However, nanotechnology must also be safe, and it is best done by incorporating sound practices into the design of nano-enabled products. A key element for the safe use of engineered nanoparticles (ENPs) is knowledge of the response of organisms when exposed to ENPs released from nano-enabled products, directly or indirectly (e.g., via treated wastewater treatment plant effluent). Traditionally, ecological risk assessment (ERA) has focused on the toxicity of ENPs, since that is clearly an important concern. However, preliminary evidence indicates that at low concentrations some ENPs may induce a stimulatory response, increasing growth rates, called hormesis. Research on predicted exposure concentrations indicates that most ENPs will be present in the environment at these low to moderate concentrations, below conventional toxicity thresholds. This proposed comprehensive approach, in collaboration with researchers from the Université de Genève in Switzerland, will provide a very strong underpinning for decision-making by (1) regulators that need to evaluate ENP-enabled products; (2) industrial product designers as they consider the different types of ENPs for their products; and (3) the public at large, by having information to decide on the use of nano-enabled products (e.g., cosmetics, sunscreens, and other personal care products). The overall goal is to address a major research gap in nanoecotoxicology concerning hormesis, as an underexplored but potentially important response of phytoplankton species, the base of the food chain, to ENPs and its implications for ERA and sustainable use of nanotechnology. The specific objectives of ENHANCER are: (1) to systematically evaluate the frequency and intensity of hormesis responses in different phytoplankton species, exposed to a large variety of ENPs; (2) to assess the effect of environmental variables on hormesis responses; (3) to improve understanding of key mechanisms driving stimulatory responses in phytoplankton species upon exposure to ENPs; (4) to explore the environmental implications of ENP-induced hormesis with novel artificial intelligence (AI) approaches; and (5) to evaluate potential ERA scenarios under various alternatives. This collaborative U.S.-Swiss project is supported by the U.S. National Science Foundation (NSF) and the Swiss National Science Foundation (SNSF), where NSF funds the U.S. investigator and SNSF funds the partners in Switzerland. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.